全文获取类型
收费全文 | 46455篇 |
免费 | 5780篇 |
国内免费 | 2596篇 |
专业分类
电工技术 | 6664篇 |
技术理论 | 1篇 |
综合类 | 5392篇 |
化学工业 | 861篇 |
金属工艺 | 823篇 |
机械仪表 | 3681篇 |
建筑科学 | 1170篇 |
矿业工程 | 975篇 |
能源动力 | 447篇 |
轻工业 | 814篇 |
水利工程 | 465篇 |
石油天然气 | 862篇 |
武器工业 | 844篇 |
无线电 | 15201篇 |
一般工业技术 | 2968篇 |
冶金工业 | 534篇 |
原子能技术 | 378篇 |
自动化技术 | 12751篇 |
出版年
2024年 | 96篇 |
2023年 | 585篇 |
2022年 | 903篇 |
2021年 | 1087篇 |
2020年 | 1142篇 |
2019年 | 808篇 |
2018年 | 817篇 |
2017年 | 1276篇 |
2016年 | 1442篇 |
2015年 | 1884篇 |
2014年 | 2911篇 |
2013年 | 2634篇 |
2012年 | 3663篇 |
2011年 | 3946篇 |
2010年 | 3038篇 |
2009年 | 3094篇 |
2008年 | 3288篇 |
2007年 | 3998篇 |
2006年 | 3449篇 |
2005年 | 3078篇 |
2004年 | 2330篇 |
2003年 | 1932篇 |
2002年 | 1451篇 |
2001年 | 1248篇 |
2000年 | 975篇 |
1999年 | 725篇 |
1998年 | 525篇 |
1997年 | 456篇 |
1996年 | 366篇 |
1995年 | 344篇 |
1994年 | 288篇 |
1993年 | 241篇 |
1992年 | 149篇 |
1991年 | 119篇 |
1990年 | 103篇 |
1989年 | 85篇 |
1988年 | 71篇 |
1987年 | 38篇 |
1986年 | 30篇 |
1985年 | 39篇 |
1984年 | 31篇 |
1983年 | 34篇 |
1982年 | 24篇 |
1981年 | 18篇 |
1980年 | 16篇 |
1979年 | 15篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1963年 | 4篇 |
1959年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 96 毫秒
1.
5G蜂窝网络发展迅猛,其覆盖面积将逐渐增大,因此使用5G蜂窝网络进行定位是有研究潜力的研究方向。本文提出一种新的深度学习技术来实现高效、高精度和低占用的定位,以代替传统指纹定位过程中繁重的指纹库生成以及距离计算。该方法建立了一个特殊的卷积神经网络,并根据5G天线信号的接收信号强度指示、相位和到达角等特征量,选择合适的输入数据格式构造样本组建训练集,对该卷积神经网络进行训练。训练得到的卷积神经网络可以替代指纹定位中的庞大指纹库,非常有利于直接在5G移动设备端实现定位。虽然卷积神经网络在训练过程中需要大量时间,但在训练完毕后直接进行分类定位的速度非常快,可以保障定位实现的实时性。本文所实现的卷积神经网络权重与偏置所占内存不到0.5 MB,且能够在实际应用环境中以95%的定位准确率以及0.1 m的平均定位精度实现高精度定位。 相似文献
2.
3.
4.
企业试图完成数字化转型,这是在竞争中谋求发展的必经之路。文章率先进行数字化转型特征、策略的概念分析,而后总结以此为背景的能力模型、企业管理能力与技术能力,最终以某公司案例完成体系构建与应用的阐述。 相似文献
5.
6.
为推进病历数字化发展,并确保其信息的安全性,将以HIS电子病历系统为基础,采用安信数字签名技术和PKI或PMI系统搭建相信并加以任用的授权服务,经过针对实际的PKC和CA的确认、委托与管控构建整体的数字签名平台,完成电子病历数字签名功能设计,以加强电子文件的完整性、真实性和不可抵赖性。最后以某医院的XML结构化的电子病历系统为基础进行项目实施,完成了医护人员通过HIS的快速身份认证,和准确地数字签名。 相似文献
7.
Liudmila Zakharova Viktoria Sharova Marina Izvolskaia 《International journal of molecular sciences》2021,22(1)
Different aspects of the reciprocal regulatory influence on the development of gonadotropin-releasing hormone (GnRH)-producing- and immune systems in the perinatal ontogenesis and their functioning in adults in normal and pathological conditions are discussed. The influence of GnRH on the development of the immune system, on the one hand, and the influence of proinflammatory cytokines on the development of the hypothalamic-pituitary-gonadal system, on the other hand, and their functioning in adult offspring are analyzed. We have focused on the effects of GnRH on the formation and functional activity of the thymus, as the central organ of the immune system, in the perinatal period. The main mechanisms of reciprocal regulation of these systems are discussed. The reproductive health of an individual is programmed by the establishment and development of physiological systems during critical periods. Regulatory epigenetic mechanisms of development are not strictly genetically controlled. These processes are characterized by a high sensitivity to various regulatory factors, which provides possible corrections for disorders. 相似文献
8.
In the past, thinking of carrying electronic devices inside our bodies was only posed by non-real scenarios. The emergence of insertable devices has changed this. Since this technology is still in its initial development stages, few studies have investigated factors that influence its acceptance. This paper analyzes the predictors of the intention to use non-medical insertable devices in two Latin American contexts. We used partial least squares structural equation modeling to examine whether six constructs predicted intention to use insertable devices. A questionnaire was administered to undergraduate students located in Colombia and Chile (n = 672). We also examined whether these predictors influenced intention differently for both of them. Four common constructs significantly and positively influenced both Chilean and Colombian respondents to use insertable devices (hedonic motivation, habit, performance expectancy, and social influence). Also, the habit has a complementary mediating effect on the relationship between social influence and behavioral intention. By contrast, effort expectations were a positive and significant predictor, but only among Chilean respondents. Findings suggest that when technologies are emerging, well-known predictors of intention (e.g., performance and effort expectations) are less influential than predictors related to self-efficacy (e.g., habit and hedonic motivation). The use of insertable devices has a significant impact on society. Thus, a better understanding of what motivates their use has implications for both academia and industry. 相似文献
9.
光遗传学是一门涉及神经科学、光学、半导体光电子学及生物医学的交叉科学.把光作为一种遗传学的研究工具,可为神经科学研究提供更高效、精准的神经调控手段,也为临床精神疾病的研究和治疗提供了新的思路.集成式注入型生物光电极是一种集刺激神经元的光源与采集生物电信号的微电极于一体的多功能生物微探针,在利用活体生物进行的光遗传学研究中有着重要的应用.文章回顾了光遗传学的历史,对集成式注入型生物光电极器件的分类和发展进行了分析,详细比较了不同类型光电极器件在结构和性能上的差异,从电学特性、噪声信号、生物兼容性及可靠性等方面进行评价.最后,对光电极器件的未来发展进行了初步的探讨. 相似文献
10.
Vijayalakshmi A Rajesh Kanna B Vijayalakshmi C 《Microscopy research and technique》2022,85(2):685-696
Malaria is a major public health concern, affecting over 3.2 billion people in 91 countries. The advent of digital microscopy and Machine learning with the aim of automating Plasmodium falciparum diagnosis extensively depends on the extracted image features. The color of the cells, plasma, and stained artifacts influence the topological, geometrical, and statistical parameters being used to extract image features. During microscopic image acquisition, custom adjustments to the condenser and color temperature controls often have an influence on the extracted statistical features. But, our human visual system sub-consciously adjusts the color and retains the originality in a different lighting environment. Despite the use of appropriate image preprocessing, findings from the literature indicate that statistical feature variations exist, allowing the risk of P. falciparum misinterpretation. In order to eliminate this pervasive variation, the current work focuses on preprocessing the extracted statistical features rather than the prepossessing of the source image. It begins with the augmentation of series images for a microscopic field by inducing illumination variations during the microscopic image acquisition stage. A set of such image series is analyzed using a Nonlinear Regression Model to generalize the relationship between microscopic images acquired with variable ambient brightness and a specific feature. The projection point of the centroid feature onto the brightness parameter is identified in the model and it is denoted as the optimum brightness factor (OBF). Using the model, the feature correction factor (CF) is calculated from the rate of change of feature values over the interval OBF, and the brightness of the test image is processed. The present work has investigated OBF for selected image textural features, namely Contrast, Homogeneity, Entropy, Energy, and Correlation individually from its co-occurrence matrices. For performance analysis, the best state-of-the-art method uses selected texture as a subset feature to evaluate the effectiveness of P. falciparum malaria classification. Then, the impact of proposed feature processing is evaluated on 274 blood smear images with and without Feature Correction (FC). As a result, the “p” value is less than .05, which leads to the result that it is highly significant and the classification accuracy and F-score of P. falciparum malaria are increased. 相似文献